Preparation And Properties Of Vacuum Cladding Ni+WC+GO Composite Cladding Layer On Cast Steel Surface

Nickel has good mechanical,physical and chemical properties.Adding suitable elements can improve its oxidation resistance,corrosion resistance,high temperature strength and certain physical properties.It is used in fields of energy development,chemical industry,electronics,navigation,aviation and aerospace,etc.In these fields Ni-based alloys are widely used.Adding tungsten carbide（WC）and graphene oxide（GO）to Ni-based alloys can improve the wear resistance and corrosion resistance of the Ni-based alloy.In this paper,vacuum cladding technology was used to prepare a Ni+WC+GO composite cladding layer on the 45 steel substrate.The structure and formation mechanism of the composite cladding layer were observed and analyzed.The composite cladding layers with different WC and GO contents were also investigated.Study on friction and wear and corrosion performance.The experimental results show that a Ni+WC+GO composite cladding layer with dense structure and good metallurgical fusion with the substrate is obtained on the surface of 45 steel,from the composite cladding layer surface to the substrate,a composite layer,a transition layer,a diffusion fusion layer and diffusion-affected layers.are sequentially formed.The main constituent phases of the cladding layer are Cr₇C₃,FeNi₃,WC,Cr₂₃C₆,Ni₃Si,C,Fe₇W₆,andγ-Ni solid solution for the composite cladding layer.FeNi₃ and Fe₇W₆ are mainly distributed in metallurgical fusion zones,and the main structure of the diffusion-affected zone is pearlite.The phase size of the composite zone is smaller than that of the interface zone.The metal particles in the composite zone change before that in the interface zone during the formation of the cladding layer.Clusters(Cr₇C₃\Cr₂₃C₆)are formed on the surface of incompletely melted Ni-based alloy particles,which grow up through the holding time and gradually become needles and are inserted into the Ni-based solid solution.The corrosion resistance of the Ni-based alloy is significantly better than that of45 steel.After the WC ceramic reinforcing phase is added to the Ni-based alloy,the corrosion resistance of the composite cladding layer is generally enhanced.When the amount of WC is about 20 wt.%,the cladding layer The best corrosion resistance is obtained.After adding the GO lubricant phase to the Ni+20%WC composite cladding layer,although the self-corrosion potential of the cladding layer is slightly reduced,the self-corrosion current density is generally reduced.The GO lubricant phase is added to the Ni+30%WC.After the composite cladding layer,the self-corrosion potential value of the cladding layer first increases and then decreases,and the self-corrosion current density increases first,then decreases and then increases.The highest self-corrosion potential value among all samples is Ni+20%WC composite For cladding layer,the lowest self-corrosion current density is Ni+30%WC+0.4%GO composite cladding layer.By comparing all cladding layers,the ultimate corrosion resistance is Ni+20%WC+0.6%GO composite Cladding layer,compared with the substrate,the current density of the composite cladding layer can be reduced by as much as 84.2%.The addition of WC hard phase to the Ni-based alloy enhances the wear resistance of the cladding layer.The friction coefficient and wear rate of the composite cladding layer decrease with the increase of the WC content.When the amount of WC is about 30 wt.%The wear resistance of the cladding layer is the best;after adding different content of GO to the Ni+30%WC composite cladding layer,the wear resistance of the cladding layer is further improved.As the amount of GO added increases,the friction of the cladding layer is increased.Both the coefficient and the wear rate show a trend of first decrease and then increase.When the GO addition amount is about 0.4 wt.%,the friction coefficient and wear rate of the cladding layer are the lowest,compared with the substrate,the friction coefficient and wear rate are reduced by 24.0%and 63.6%respectively,and at this time,the best lubricating and antiwear effect is exhibited.